The prior art has provided pressure washers for use in washing surfaces such as wood, tile, concrete and the like. A pressure washer typically comprises a source of a pressurized washing fluid that fluidically communicates with an operator wand via a high-pressure hose. The prior art further has provided numerous hoses for use in conjunction with such pressure washers, which hoses typically comprise a jacketed core of thermoplastic material or other material. Such conventional pressure washer hoses are capable of accommodating the moderately high pressures associated with conventional power washers while leaving a satisfactory margin of safety. Consumer applications mandate a margin of safety of 300% (i.e., a burst strength of 400% or four times the rated pressure). Thus, for example, a hose having a nominal rating of 1000 psi will require, at a minimum, that the hose be able to accommodate a pressure of at least about 4000 psi as measured, for example, in accordance with SAE J17. The prior art has provided a number of pressure washer hoses that have such a nominal rating with a 300% safety margin.
Hoses designed for use in consumer applications must be sufficiently flexible to accommodate the demands of consumer pressure washers. Recently, U.S. Pat. No. 5,964,409, which is hereby incorporated by reference in its entirety, disclosed a satisfactory flexible thermoplastic pressure-washer hose that is designed to operate at pressures greater than about 2000 psi, with the 300% safety margin conventionally required. The hoses therein disclosed are suitable for high pressure applications wherein the pressure generated by the pressure washer exceeds about 2000 psi. The hoses discussed in the '409 patent are suitable for use at pressures ranging up to about 3000 psi.
The prior art has further provided numerous high-pressure hoses for use in applications other than pressure washers, such as industrial fire protection hoses and chemically resistant hoses for industrial equipment. Typically, such a hose comprises an inner tube covered with a reinforcing braided sheath, which, in turn, is covered by an outer jacket. Known consumer grade high-pressure hoses typically are made of very stiff materials to accommodate the high pressures expected under operating conditions, and little or no thought typically is paid to the flexibility of the hose. As a result, such hoses generally are unsuitable for use with consumer pressure washer applications, which mandate that the hose be highly flexible. Moreover, many such hoses tend to kink if bent past an angle of about 90° over a short distance, which kinking is disruptive of the flow of pressurized fluid through the hose and potentially detrimental to the hose and to the equipment serviced by the hose.
The prior art has further taught the use of corrugated hoses in an effort to increase the flexibility of the hose. Such corrugated hoses, however, are expensive to manufacture, and are thus not well suited for use with consumer pressure washers.
Although the hoses disclosed in the prior '409 patent have excellent properties and are satisfactory in pressure-washer applications, there remains room for improvement. Specifically, it is desired to provide a hose that can accommodate for pressures of greater than about 12,000 psi (such hose having a rated operating pressure of greater than about 3,000 psi) and preferably a hose that can accommodate pressures of up to about 16,000 psi (a rated operating pressure of about 4,000 psi), yet that remains flexible and that can be bent through a angle of 180° over a short distance without kinking.